Screw thread lock



' Oct. 11, 1932. LLEWELLYN 1,881,749

SCREW THREA LOCK Filed ec. 6, 1930 5 Z 1/1, /9\\\\\ 4 5 I As s am tr I a fillister head screw suflicient to enable those Patented Get. 11, 1932 PATENT, OFFICE ERNEST R. LLEWELLYN, OF ARLINGTON, MASSACHUSETTS SCREW THREAD LOCK Application filed December 6, 1930. Serial No. 500,538.

This invention relates in general to means for preventing relative rotary motion in a given direction between two members and while not limited thereto is particularly adapted to externally and corelated internal- 1y threaded members.

Heretofore various means have been employed to retain threaded members in positiverelation, each means having had its attendant disadvantages either in the manner of cost in manufacturing or utility in practice. Retaining two threaded members in position is difficult, due to the cammingaction of the thread which will, under vibration, cause a s reverse or backing motion between the thread ed members. Most methods for preventing this difiiculty, other than the cost in manufacturing, in many instances require additional parts, as for example, the use of the so-termed jamb screw after the first screw has been positioned in a tapped hole.

To eliminate the above disadvantages I have provided the externally threaded member with a locking device that permits the rotating of the member in either direction but restrains contrawise movement to the r0- tated direction. This locking device may be applied to a screw thread without the necessity of special tools or special design of threads to accomplish the desired'results. My

present locking device being an im rovement of my co-pending application, erial No.

The object of my present'invention is to 5 provide a simple and efiicient thread lock to prevent contrawise movement that can be economically manufactured and applied to the standard form of threads.

With the above and other objects in View my invention consists in the novel application and arrangement of thread locking means hereinafter described and more specifically pointed out in the appended claims.

In the accompanying drawing I have illusated my locking device in conjunction with skilled in the art to understand the construcnot to be construed as limiting my device thereto as the applicationmay be utilized in various designs and types of'screw's.

Referring to the drawing Fig. 1 is a side view of a fillister head screw, the threaded portion being shown in partial section and having my locking device contained therein; 7 1 I Fig. 2 is a transverse section taken substantially along line 22, Fig. 1, viewing in the direction of arrow a, same figure;

Fig; 3 ma view corresponding to Fig. 2 but shows the locking device in'a different position;

Fig. 4 is a side View of a screw showing a modified construction and application of my locking device; and, v i

Fig. 5 is a plan view of the locking device as shown at Fig. 4,'viewing in direction of in the direction indicated by the arrow, Fig.

2, the pin 14 is flexed and assumes a position "as illustrated by the full lines, the outer end 14a engaging with the root of the complemental internal thread formed in the member15. The pin 14in the position as shown by full lines Fig. 2, restrains the screw 10 from rotating in a direction opposite to that indicated by the arrow. 7

As the screw 10 is forced in the direction as indicated by the arrow, Fig. 3, the pin 14 is flexed substantially through a path as shown by the broken lines until it assumes the position as illustrated by the full lines, Fig. 3. This restrains the screw 10 from turning in a direction opposite to that indicated by the arrow. tion and operation thereof. While I have I illustrated a particular type of screw it is At Fig. 4 I have shown a screw having a threaded body 16 with a turned portion 17 of less diameter than the root of the threads,

6O distance to project beyond the radius of said internally threaded bore, said element bering capable of bending on engagement with said bore to provide for free rotation of said externally threaded member in onedirection this portion 17 may be formed as shown adj acent the threads or intermediate relative to the threads and body. The reduced portion 17 is provided with a transverse pin member 18 of greater length than the outside diameter of the threads, the outer ends 18a being adapted to engage with therootof the thread formed {in the internally threaded 'member to restrain contrawise movement."

Having thus described my invention it will be evident to those skille'dinthei art that.

many changes and modifications may be made therein without departing from the spirit and scope thereof, therefore I do not but being adapted to bind against said internally threaded bore and thereby oppose rotation of the latter member in the opposite direction, whereby said element serves to retain said externally threaded member in said bore.

In testimony whereof I'havehereunto set myhand; v I a ERNEST R. LLEWELLYN.

wish to be limitedto the specific details hereindisclosed-orlimited in application to the p conventional formiof threaded screw as 'illustrated for convenience, but what I claim is 1. An internally threaded bore, an extern'erend portion of said threadedmem'ber, a

,nally threaded member adapted to be en gaged in saidbore, a recess formed in the inradially movable resilient member supportan internally threaded bore, of an ex ternally threaded member similarly threaded to engage the threads in said bore, said 1 ed in and normally disposed at right angles to the axisof said'threaded member, said .2. ,An internally threaded bore, an 7 exterradialmember being greater inlength than V l l the radius ,of said threaded memberto enjgage' said internally threaded bore.

nally'threaded-memberadapted to {be ensaid internally threaded bore.

, T3. An'internallythreaded'bore, an exte'rvnally'threaded member adapted to'be .en-

gaged in said'bore, said'member having a rep threaded bore. v e

4;. The combination with a member havexternally threaded member having a cut away portion adjacent the periphery 'thereof a resilient element carriedby said externally threaded member, said'element be 'ing disposed transversely of the axis .ofsaid externally threaded member j and extending,

through said cutaway portion a sufficient d'uced body portion, aresilient inember snpported in said body portion, said-resilient V imemberhaving opposite projecting ends norfmally disposed at opposite angles to the'axis iof said threaded member to engage 'said' 

